From SCF version 3.0 onwards the in memory structures and the data on the disk are not in the same format. The overview of the data on disk for the different versions is summarised below.

Versions 1 and 2 (Note Samples1 can be replaced by Samples2 as appropriate.) Length in bytes Data --------------------------------------------------------------------- 128 header Number of samples * 4 * sample size Samples1 or Samples2 structure Number of bases * 12 Base structure Comments size Comments Private data size private data Version 3 Length in bytes Data --------------------------------------------------------------------------- 128 header Number of samples * sample size Samples for A trace Number of samples * sample size Samples for C trace Number of samples * sample size Samples for G trace Number of samples * sample size Samples for T trace Number of bases * 4 Offset into peak index for each base Number of bases Accuracy estimate bases being 'A' Number of bases Accuracy estimate bases being 'C' Number of bases Accuracy estimate bases being 'G' Number of bases Accuracy estimate bases being 'T' Number of bases The called bases Number of bases * 3 Reserved for future use Comments size Comments Private data size Private data ---------------------------------------------------------------------------

URL: http://www.mrc-lmb.cam.ac.uk/pubseq/manual/formats_8.html